Phenyl methyl dialkoxy silane-polyhydric alcohol-dicarboxylic acid or anhydride reaction



Patented Feb. 10, 1953 UNITED STATES PATENT OFFICE PHENYL METHYLDIALKOXY SILANE-POLY- HYDRIC ALCOHOL-DICARBOXYLIC ACID R ANHYDRIDEREACTION No Drawing. Application September 28, 1949, Serial No. 118,446

2 Claims. 1

This invention relates to copolymers of a silane, an alcohol and acarboxylic acid.

The applicants copending application, Serial Number 59,414, filedNovember 10, 1948, now U. S. Patent No. 2,584,351, and assigned to theassignee of this invention, discloses and claims a method of preparingcopolymers which involves reacting an alcohol and a silane in suchproportions that there is always an excess of alcoholic hydroxylsremaining in the reaction product and thereafter reacting the hydroxylcontaining material with a polybasic acid.

This invention relates to a method of preparing copolymers by reacting apolybasic acid with a silane-alcchol reaction product in which there areno hydroxyl groups. Thus, this invention relates to a new method ofpreparing three component copolymers containing an alcohol, a silane andan acid.

In accordance with this invention a silane of the type RzSiXz where R isan alkyl or monocyclic aryl radical and X is chlorine or alkoxy isreacted with an equivalent amount of a dihydric alcohol and theresulting product is reacted with a polycarboxylic acid or an anhydridethereof in amount such that the ratio of the number of acid functionalgroups to the sum of the number of silane X radicals lus the number ofalcoholic hydroxyl radicals is from 0.01 to 1.

In this invention the term acid functional groups has reference to thereactive groups of the acids. Each carboxyl radical constitutes onefunctional group while each anhydride group constitutes two functionalgroups. Thus, for example, both phthalic acid and phthalic anhydridehave two functional groups.

The silane and the alcohol are reacted by bringing the two into contactwhereupon condensation takes place with the elimination of HCl or amonohydric alcohol and the formation of a polyester having siOClinkages. Since the reactants are employed in equivalent amounts,essentially no alcoholic hydroxyls remain in the reaction product. Whenalkoxy silanes are used it is desirable to employ a trace of a strongacid such as HCl or H2504 as a catalyst and to carry out the reactionunder such conditions of temperature and pressure that the monohydrica1- cohol will be removed from the reaction mixture.

The silane-alcohol condensation product is reacted with a polycarboxylicacid or anhydride thereof preferably at a temperature between 100 C. and300 0. Under these conditions of temperature reaction begins at once andproceeds smoothly as is shown by the progressive lowering of the acidnumber. The acid number of a material is the number of milligrams of KOHwhich are required to neutralize 1 g. of the material. When anhydridesare employed no water is eliminated from the reaction mixture. Whenacids are used water is eliminated due to the formation of acidanhydrides. It is believed that these in turn react with thesilane-alcohol ester to produce the products of this invention.

One mechanism by which the reaction may occur is by the splitting of thesilane-alcohol ester linkage in accordance with the following equation:

[ i ORO'-']m R(GO)2O [i O0ORCO0R,.O],, Thus it can be seen that polymersof this invention are composed of units having a silane group attachedto the acid unit through a $106 linkage and an alcohol unit attached tothe acid unit through a COC linkage.

In those cases where all three components are difunctional, the productsobtained by the method of this invention are viscous liquids. When theacid employed is at least trifunctional the product may be across-linked insoluble gel.

This invention includes Within its scope any alkoxy or chlorosilane inwhich the R radicals are alkyl such as methyl, ethyl, propyl andoctadecyl or monocyclic aryl such as phenyl, tolyl and chlorophenyl andany dihydric alcohol of the type HOROH where R is a divalent organicradical such as alkylene, phenylene or cyclic alkylenes and anycarboxylic acid having at least two carboxyl groups or anhydridesthereof.

Examples of such acids are saturated aliphatic acids such as succinic,adipic, oxalic and sebacic; unsaturated aliphatic acids such as fumaricand maleic; and aryl carboxylic acids such as phthalic, trimellitic andmellitic.

The products of this invention are useful as plasticizers for siloxaneand organic resins, as paint vehicles and as coatings for electricalconductors. The products are of particular importance because theycombine a thermal stability approaching that of polysiloxanes withdesirable mechanical properties of organic resins.

The following examples are illustrative only.

Example 1 2 g. mols of ethylene glycol and 2 g. mols ofphenylmethyldiethoxysilane were mixed and heated at 96 C. for hour. Themixture was then heated at 200 C. as 173.5 g. of ethyl alcohol wereremoved. The reaction mixture was cooled to C. and 0.5 g. mols ofphthalic anhydride Hrs. heated at 200 C.

The product was a clear viscous fluid;

Example 2 were mixed with 0.25 g. mole of maleic anhydride and heated asfollows:

Hrs. heated Acid number During the reaction only 0.15 g. of water was 1obtained showing that the reactiondid. not proceed through combinationof the acid withOI-I groups. The saponification number of the. re.-

action product was found to be 149 thus showing the acid was presentedin combined form.

Example 3 189 g. of the phenylmethyldiethoxysilaneethylene glycolreactionv product of'Example 2 was mixed with 0.25 g; mols of fumaricacid and the mixture was heatedat 160 C. with the results shown below:

Acid

Hrs. heated Number In this case 8.9 g. of water distilled which. wasformed by the condensation of the fumaric acid 4 to form polymericanhydrides thereof. The saponification number of the finished productwas 138.

Example 4 1.5 g. molsof. phenylethyldichlorosilane was mixed with 1.5 g.mols of trimethylene glycol. Reaction proceeded at room temperature withthe elimination of HCl. When this reaction product is mixed with 2 g.mols of trimellitic acid and heated at a temperature of 160 C. a viscousreaction product is obtained.

That which is claimed is:

1. The method of preparing copolymeric materials which comprisesreacting phenylmethyldiethoxysilane with an equimolecular amount ofethylene glycol and reacting the resulting product at a temperaturebetween 100 C. and 300 C., with an acidic compound selected from thegroup consisting of dicarboxylic acids and anhydrides thereof, in amountsuch that the ratio of the number of. acid functional groups to the sumof the number of ethoxyl radicals plus hydroxyl radicals is from 0.01 to1.

2. The method of preparing copolymeric materials which comprisesreacting a phenylmethyldialkoxysilane with an equal molecular amount ofa dihydric alcohol and reacting the resulting product at a temperaturebetween 100 C. and 300 0., with an acidic compound selected from thegroup consisting of dicarboxylicacids and anhydrides there, in amountsuch that the ratio of the number of acid fundamental groups to the sumof the number of alkoxy radicals plus hydroxyl radicals is from 0.01 to1.

MELVIN J. HUNTER. LAWRENCE A. RAUNER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,386,793 Hanford Oct. 16, 19452,413,582 Rust et a1 Dec. 31, 1946 2,500,843 MacKenzie et a1. Mar. 14,1950 2,529,956 Myles et a1 Nov. 14, 1950 FOREIGN PATENTS Number CountryDate 583,754 Great Britain Dec. 30, 1946

2. THE METHOD OF PREPARING COPOLYMERIC MATERIALS WHICH COMPRISESREACTING A PHENYLMETHYLDIALKOXYSILANE WITH AN EQUAL MOLECULAR AMOUNT OFA DIHYDRIC ALCOHOL AND REACTING THE RESULTING PRODUCT AT A TEMPERATUREBETWEEN 100* C. AND 300* C., WITH AN ACIDIC COMPOUND SELECTED FROM THEGROUP CONSISTING OF DICARBOXYLIC ACIDS AND ANHYDRIDES THERE, IN AMOUNTSUCH THAT THE RATIO OF THE NUMBER OF ACID FUNDAMENTAL GROUPS TO THE SUMOF THE NUMBER OF ALKOXY RADICALS PLUS HYDROXYL RADICALS IS FROM 0.01 TO1.